Detecting a {\mu}{\tau}-philic Z' boson via photon initiated processes at the LHC

Abstract

Discrepancy between the measured value and the Standard Model prediction of the muon anomalous magnetic moment is a possible hint for new physics. A $Z^{\prime }$ particle with $\mu \tau$ flavor violating couplings can give a large contribution to the muon anomalous magnetic moment due to the $\tau$ mass enhancement at the one-loop level, and is known to explain the above discrepancy. In this paper, we study the potential of the Large Hadron Collider (LHC) for detecting such a $Z^{\prime }$ boson via the $pp\to {\mu }^{-}{\mu }^{-}{\tau }^{+}{\tau }^{+}$ process. Earlier studies in the literature only considered the production channel with quark initial states ($pp\to q\bar{q}\to {\mu }^{-}{\mu }^{-}{\tau }^{+}{\tau }^{+}$). Here, we show that the photon initiated process, $pp\to \gamma \gamma \to {\mu }^{-}{\mu }^{-}{\tau }^{+}{\tau }^{+}$, is in fact the dominant production mode, for a heavy $Z^{\prime }$ boson of mass greater than a few hundred GeV. The potential of the high luminosity (HL) LHC is also considered.

Comments: 11 pages, 6 figures